There''s no one test to diagnose Alzheimer''s disease. Typically, doctors
start the diagnostic process by ruling out other diseases and conditions that
also can cause memory loss. Small, undetected strokes, for example, can cause
dementia by temporarily interrupting blood flow to the brain. People with
Parkinson''s disease, a degenerative nerve disorder, also can develop dementia.
Depression, too, can cause lapses in memory. In addition, many older adults are
on multiple medications that may impair their ability to think clearly. To help
distinguish Alzheimer''s disease from other causes of memory loss, doctors
typically rely on the following: Medical history. Doctors may
ask about a person''s general health and past medical problems. They''ll want to
know about any problems a person may have in carrying out daily activities. If
possible, doctors will also want to speak with a person''s family or friends to
get more information. Basic medical tests. Blood tests may be
done to help doctors rule out other potential causes of the dementia, such as
thyroid disorders or vitamin deficiencies. Mental status evaluation.
These tests screen memory, problem-solving abilities, attention spans, counting
skills and language. They help doctors pinpoint specific problems a person may
have with cognition. For instance, doctors might test recent and long-term
memory by asking: What day is it today? Or: When was World War II? Recall tests
are another example. Doctors may list familiar objects, and then ask a person
to repeat them immediately, and again five minutes later. Neuropsychological
testing. Sometimes doctors undertake a more extensive assessment of
memory, problem-solving abilities, attention spans, counting skills and
language. This is especially helpful in trying to detect Alzheimer''s and other
dementias at an early stage. Doctors use formal psychological tests to
determine if a person''s mental abilities are as expected for his or her age and
education. The patterns of any mental deficits observed during
neuropsychological testing can help doctors sort out possible causes of
dementia. Brain scans. Doctors may want to take a picture of
the brain using a brain scan. Several types of brain scans are available —
including a computerized tomography (CT) scan, a magnetic resonance imaging
(MRI) scan and a positron emission tomography (PET) scan. By looking at images
of the brain, doctors may be able to pinpoint any visible abnormalities.
Researchers are studying whether brain scans can eventually be used to detect
an increased risk of Alzheimer''s in healthy people before symptoms begin. Using
the methods above, doctors can accurately diagnose 90 percent of Alzheimer''s
cases. Alzheimer''s can be diagnosed with complete accuracy only after death,
using a microscopic examination of brain tissue, which checks for plaques and
tangles. Genetic testing for Alzheimer''s is in its beginning stages. Blood
tests are available that can tell whether a person carries the genetic
mutations believed to be associated with Alzheimer''s, but the tests can''t tell
who will or will not get the disease.